Optical system for prism-carrying devices.



E. BERNICK.

OPTICAL SYSTEM FOR PRISM CARRYING DEV OES.

APPLICATION run 001:. 23, 1908.

1,104,769. Patented July 28, 191 1 UNITED STATES OFFICE.

ERNST BERNICK, 0F FRIEDENA'U. NEAR BERLIN. GERMANY, ASSIGNOR TO THE FIRM 0F OPTISCHE ANSTAL'I C. P. GOERZ AKTIENGESELLSCHAFT, OF FRIEDENAU, NEAR BERLIN, GERMANY.

Specification of Letters Patent.

Patented Jilly 28, 1 91.4.

Application filed October 23, 1908. Serial No. 459,208.

To all 017mm 1' t may, concern Be, it known that, It, ERNST Brennan. :1 ritizen of the German Empire, residing at 14 Diirin gs'lrasse. Friedennu, near Berlin. (Hermann have invented certain new and nsel'nl improvements in Optical Systems for Prisnrt arrying Deviees, of Whieh the followin; is a, speeiliention.

In various instrmnents. more partienlarly in Slr-(ttllttl hase'line telemeters and photometers. it is net'essary to deflect into one dirertion rays coming from opposite (li n tions.

The pr sent invention relates to a v in-- hination ot' prisms \vhieh serve this purpose and eomprises. in a manner Whieh is in itself kn wn, two prisms eemented together. with the ement snrt'aee prm'ided in part with a retlet-iing eoatin and forming t gether a prism hody whieh exposes snhstarr tialiy parallel snrl'aees to rays ruining from opposite direetions.

ln lin -n prism combinations of this kind it. is e sential that the rays coming from opposite direetions and falling np n i'llt pi ism e mhinntion to leave the latter as a single run are laterally displa ed relatively to eaeh other. and when the prism eomhination is wed for example as or-nlar prism in a base line telemeter this gives rise to the disadvantage that; the ohjeetives mint also he disphn'ed relatively to eaeh other unless with eo-:1. {ial Ohjt-(tiVts speeial ptoi'ision is made for eompen atiing the latxral displacement of the axial rnvs produeed hy the ocular prism.

The present invention relates to a prism eomhination oi the kind referred to. \Vlli('ll dir tly muses (ti-ttXltll rays eoming from opposite direeti ns t pass out of it united into a single ray.

Two ex mples of the new prism eomhinalion applied to hase line telemeters are illustrated in th annexed drawing.

Figure 1 shows one example of the combination in plan and side view. Fig. 2 shows a moditie 'l form. nlwo in plan and side view. Fi z. 3 shows the prism eomhinntion of Fig. 1 in t-mtjnnetion with the optical elements of a hasu line teltmetcr. Fig. 4 shows the eomhination according to Fig. 2 in conjunction with the optieal elements of a, base line telemeter.

in the arrangement. shown in Fig. 1 the prism eon'ihination comprises a triangular right. prism and a root shnped prism 2 eemented thereto, the cement snrt'aee being in part eon-red hr :1. relleeting muting 3, t'orming :1 mirror on hoth sides. This prism roinhimltion has two snhstantiallv parallel snrtaees l and 7 serving as entrnnee surlaues for the rays to he tl(ll(t'it'4l into one direetion h the romhination. The path of the rays is indieated in the drawing. The rays eoming from one side are direetly thrown out of the prism hy relleetion from the respertire r'lllftl 't of the coating 3, heren the rays eoming from the opposite ide are retleeted hy the other side of the mirror to the roof surtaee and are so de llerteil and reversed hy douhle refleeti n at the roof that they are \erti nlly displaeed hel'ore they again strike the eement snrfaee of the two prisms, and then pass thronglr the inn-rated portion of the snr fare and pass out of the prism in the same direetion as the rays (-oming from the opposite direetion.

The, mmlifieation shown in Fig. 2 is distinguished from that shown in Fig. l hy the dill'erent position (it the root snrt'aee of the prism and hy the addition of another retleeting snrt'nee it to the root' surface, forming with the latter a somalled triple mirror. In this eonstrnl-tion the rays eoming l'rom one side are nlSo directly thrown ut of the prism hy the relieeting eonting ot' the cement snri'aee. Whereas the opposite side of the mirror throws the rays eominggfrom the other side in part over the roof snrl'aee to the snpplementarv relieeting snrtnee 3, and thenee out of the prism. past the retleeting eontinfl. and in part over the retleeting surfxu-e t; to the rontsnrl'm-es, hy which they are thrown out of the prism hody.

The essential ditteren e hetween the eonstrnetions shown in l in's. l and 2 respeetively heeomes apparent when the eomhinafit)! are wed in eonjnneti n with imam prmlnein; distain 'r-nnnsnring instruments ete.. and will he indicated in the following description of the employment of the prism ornbinations in base line telemeters.

\Vith the prism combination shown in Fig. 1, used in conjunction with an inverting basis distance measurer as shown in Fig. 3 the prism combination serves as ocular prism to project to an ocular 9 rays coming through objectives 7 and 8 from the end points of a base, so that images of dis! ant objects appear at both sides of a dividing line in the field of view which is formed by the edge of the coating 3. In order to obtain with the ocular prism constructed as shown in Fig. 3, on opposite sides of the dividing line images of distant. objects which are simply inverted, such as would result by" rotation through 180 in space, with the" dividing line as an axis, it is necessary that an even number of reflectors are placed in front of the ocular prism on one side, and an uneven number on the other, as shown in the drawing, where there is a pentagonal prism 10 on one side and a threecornercd rectangular prism 11 on the other side.

With the arrangement shown in Fig. 4 of the prism combination of Fig. 2 in conjunc tion with a base line telemeter, it is not necessary to have unequal numbers of reflectors on both sides of the ocular prism. In Fig. 4, accordingly, the usual arrangement. of a single pentagonal prism 12 at each side of the ocular prism is illustrated.

hat I claim is:

1. A prism combination for deflecting into the same direction rays coming from opposite directions, comprising two prisms cemented together, having substantially parallel surfaces facing in the directions from which the rays enter, one of which is provided with a roof surface, a coating or layer in the cement surface between the prisms extending through a part of same and being retl ctive on both sides and so arranged in rel, ion to said roof surface that the rays striking the reflective coating on one side pass, after reflection by the roof-surfaces, to the nonreflecting part of the cement surface, through which they whereas the rays striking the other side of the reflective coating pass after reflection directly out of the prism body.

2. A prism combination for deflecting into the same direction rays coming from opposite directions, comprising two prisms cemented together, having substantially par allcl surfaces facing in the directions from which the rays enter, one of which is provided with a roof surface, a further reflecting surface at right angles to the edge of said roof surface forming a so-called triple mirror with same, a coating or layer in the cement surface between the prisms extending through a part of same and being reflective on both sides and so arranged i'ii'relation to the faces of said triple mirror that the rays striking the reflective coating on one side pass after reflection by the fares of the triple mirror to the non-reflecting part of the cement surface. through which they pass, whereas the rays striking the other side of the reflective coating pass after reflection directly out of the prisu'i-lmdy, for the purpose of producing images of the objects at both sides of the prism ccm iruition, inverted relatively to each other.

An optical distance measuring instrument comprising two objectives and two sets of reflecting devices arranged at a distance from each other, each of the objectives adapted to cooperate with one of the two sets of reflecting devices, at least one of said sets of reflecting devices having an even number of reflecting surfaces, an in e uniting body or ocular prism between said tw objectives and bli'S of reflecting devices, and an ocular in front of said image uniting body or ocular prism, said ocular prism con'iprising two prisms cemented together having substantially parallel surfaces fac in; in the direction toward said two objectives and sets of reflecting devices, one of which is provided with a roof surface, a coating or layer in the cement surface be tween the prisms extending through a part of same and being reflective on both sides and so arranged in relation to said roof surface that the rays striking the reflective coating on one side pass after reflection. by the roof surfaces to the non-reflecting part. of the cement surfacethrough which they pass toward the ocular, whereas the rays striking the other side of the reflective coating pass after reflection directly out of the prisnrbody likewise toward the ocular.

4. An optical distance measuring instrument comprising two objectives and two sets of reflecting devices arranged at a distance from each other, each of the two objectives adapted to cooperate with one of the two sets of reflecting devices, the said sets of reflecting dc vices differing from each other by an even number (inclusive zero) of reflecting surfaces, an image uniting body or ocular prism between said two objectives and sets of reflecting devices. and an ocular in front of said image uniting body or ocular prism, said ocular prism comprising two prisms cemented together having substantially parallel surfaces facing in the directions toward said two objectives and reflectors cooperating therewith, one of which is provided with a roof surface. a further refleeting surface at right angles to the edge of said roof surface forming a so-called triple mirror with same, a coating or layer in the cement surface between the prisms extending through a part of same and being reflective on both sides and so arranged in relation to the faces of said triple mirror that the rays striking th reflective coating on {me was afikr refiecfiml by the faces 01? the. M pie 11 rig: (2Q iha mnawflwting part 0? the as; I at" siswfac flaming; wliiefi Um" mus i iwarfi iha Dfflflll', when! 11% Ring Hm other side of the rirfieci-ve a 5 pass ,x-tez reflection directly out of m; gnusuvbmiy HLIQWISctoward the ocular.

i In testimony wherenf I have'signed this; rspecifi atinn in the presence of two subm'bing Witnesses.

; ERNST BERNICK.

3 W itnesses:

% I'IENRY IIASIER,

i \Yoummm HAUPT. 

